THE EFFECT OF FATTY ACID BUFFER SYSTEMS ON THE APPARENT VISCOSITY OF THE ARBACIA EGG, WITH ESPECIAL REFERENCE TO THE QUESTION OF CELL PERMEABILITY TO IONS

¹ From the Department of Physiology, University of Pennsylvania, Philadelphia, and the Marine Biological Laboratory, Woods Hole, Massachusetts

The effects of the pH of the medium on the apparent viscosity of Arbacia eggs have been studied by means of an adaptation of the centrifuge method.

It was found that the degree to which fatty acids decrease the protoplasmic viscosity can be altered by the presence of the salt of the acid, apparently by virtue of the influence of the salt on the intracellular hydrogen ion equilibria. Similar pH variations of the medium produced by mineral acids do not affect viscosity.

These results offer confirmation, from a separate type of evidence, of Smith's observation that the salts of penetrating acids differ from other ionized compounds in apparently being able to penetrate the living cell much more easily. It is suggested that cell permeability to this type of salt could be explained as resulting from a cation exchange of external base for internal hydrogen ions from the penetrating acid, the entrance of the salt therefore being accomplished without the direct transfer of its anions.